The IEEE 802.11p is a standard in a vehicular communication system, known as Wireless Access in Vehicular Environment (WAVE). An implementation of that standard as the MAC Protocol in a high-density of nodes in Vehicular Ad-Hoc Networks (VANETs) may create a performance drawback, in particular for packet loss and delay whenever collisions happen. Introducing Time Division Multiple Access (TDMA) schemes can improve the performance. However, TDMA scheduling is difficult to manage the case of high-density of traffic, the high mobility of vehicles, and dynamic network topology. This journal proposes a clustered-based TDMA by traffic priority in VANETs. The clustered traffic is defined as high and low traffic priority and embedded in TDMA MAC Header. The evaluation result obtained through NS3 Simulator shows that the proposed approach performed better in a high-density of nodes.